As a rule, the space requirement in aeroplanes and in aircraft in general is relatively limited. Due to the fact that passengers, in particular in the case of long-haul flights, are in an aircraft for a relatively long time and in doing so have relatively little space available results in endeavours not only to use the existing small space as efficiently as possible, but also to achieve the largest possible spatial effect from the small space available.
A particular region of space management relates to the design of ceilings in common areas in aircraft, i.e. areas that are visited by several passengers during the flight or during entering and leaving the aircraft. Common areas are, in particular, entrance regions, ceilings, sanitary installations etc. As a rule, these regions are predominantly used with passengers in an upright position so that the clear space between a passenger's head and the ceiling is relatively small when compared to the situation, for example, in a seating area in which the clear space between a seated passenger and the ceiling is often significantly larger.
This results in the need, in the region of common areas, to provide devices and in particular illumination devices that provide to passengers the impression of larger size and width than the size and width that is actually present.